international lottery by e-mail

I've been receiving a lot of spams in my e-mail with all the nonsense offering me money by joining an international lottery. they even presented me my winning cheque that enclosed a 1 million euro with my name and address on it. in order to claim my prize, i need to have a credit card and post my credit card number on it. is this really a true lottery or just one of internet scams?

the best thing always to do in such affairs and emails is.. to ignore. BUT, if you feel like playing a few pranks yourself... respond, asking them for more details. and proof of their claim. Never giving out the personal details. however.
I have often asked for personal photographs also. and, I am surprised to receive quite a few revealing and modern photos of NIGERIAN, girls of AFRICAN origin.